#include <stdio.h>
#include <string.h>

#include "sdkconfig.h"
#include "esp_log.h"

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

#include "u8g2_esp32_hal.h"

static const char *TAG = "u8g2_hal";
static const unsigned int I2C_TIMEOUT_MS = 1000;

static spi_device_handle_t handle_spi;	// SPI handle.
static i2c_cmd_handle_t handle_i2c;		// I2C handle.
static u8g2_esp32_hal_t u8g2_esp32_hal; // HAL state data.

#undef ESP_ERROR_CHECK
#define ESP_ERROR_CHECK(x)                         \
	do                                             \
	{                                              \
		esp_err_t rc = (x);                        \
		if (rc != ESP_OK)                          \
		{                                          \
			ESP_LOGE("err", "esp_err_t = %d", rc); \
			assert(0 && #x);                       \
		}                                          \
	} while (0);

/*
 * Initialze the ESP32 HAL.
 */
void u8g2_esp32_hal_init(u8g2_esp32_hal_t u8g2_esp32_hal_param)
{
	u8g2_esp32_hal = u8g2_esp32_hal_param;
} // u8g2_esp32_hal_init

/*
 * HAL callback function as prescribed by the U8G2 library.  This callback is invoked
 * to handle SPI communications.
 */
uint8_t u8g2_esp32_spi_byte_cb(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
{
	ESP_LOGD(TAG, "spi_byte_cb: Received a msg: %d, arg_int: %d, arg_ptr: %p", msg, arg_int, arg_ptr);
	switch (msg)
	{
	case U8X8_MSG_BYTE_SET_DC:
		if (u8g2_esp32_hal.dc != U8G2_ESP32_HAL_UNDEFINED)
		{
			gpio_set_level(u8g2_esp32_hal.dc, arg_int);
		}
		break;

	case U8X8_MSG_BYTE_INIT:
	{
		if (u8g2_esp32_hal.clk == U8G2_ESP32_HAL_UNDEFINED ||
			u8g2_esp32_hal.mosi == U8G2_ESP32_HAL_UNDEFINED ||
			u8g2_esp32_hal.cs == U8G2_ESP32_HAL_UNDEFINED)
		{
			break;
		}

		spi_bus_config_t bus_config;
		memset(&bus_config, 0, sizeof(spi_bus_config_t));
		bus_config.sclk_io_num = u8g2_esp32_hal.clk;  // CLK
		bus_config.mosi_io_num = u8g2_esp32_hal.mosi; // MOSI
		bus_config.miso_io_num = -1;				  // MISO
		bus_config.quadwp_io_num = -1;				  // Not used
		bus_config.quadhd_io_num = -1;				  // Not used
		//ESP_LOGI(TAG, "... Initializing bus.");
		ESP_ERROR_CHECK(spi_bus_initialize(HSPI_HOST, &bus_config, 1));

		spi_device_interface_config_t dev_config;
		dev_config.address_bits = 0;
		dev_config.command_bits = 0;
		dev_config.dummy_bits = 0;
		dev_config.mode = 0;
		dev_config.duty_cycle_pos = 0;
		dev_config.cs_ena_posttrans = 0;
		dev_config.cs_ena_pretrans = 0;
		dev_config.clock_speed_hz = 10000;
		dev_config.spics_io_num = u8g2_esp32_hal.cs;
		dev_config.flags = 0;
		dev_config.queue_size = 200;
		dev_config.pre_cb = NULL;
		dev_config.post_cb = NULL;
		//ESP_LOGI(TAG, "... Adding device bus.");
		ESP_ERROR_CHECK(spi_bus_add_device(HSPI_HOST, &dev_config, &handle_spi));

		break;
	}

	case U8X8_MSG_BYTE_SEND:
	{
		spi_transaction_t trans_desc;
		trans_desc.addr = 0;
		trans_desc.cmd = 0;
		trans_desc.flags = 0;
		trans_desc.length = 8 * arg_int; // Number of bits NOT number of bytes.
		trans_desc.rxlength = 0;
		trans_desc.tx_buffer = arg_ptr;
		trans_desc.rx_buffer = NULL;

		//ESP_LOGI(TAG, "... Transmitting %d bytes.", arg_int);
		ESP_ERROR_CHECK(spi_device_transmit(handle_spi, &trans_desc));
		break;
	}
	}
	return 0;
} // u8g2_esp32_spi_byte_cb

/*
 * HAL callback function as prescribed by the U8G2 library.  This callback is invoked
 * to handle I2C communications.
 */
uint8_t u8g2_esp32_i2c_byte_cb(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
{
	ESP_LOGD(TAG, "i2c_cb: Received a msg: %d, arg_int: %d, arg_ptr: %p", msg, arg_int, arg_ptr);

	switch (msg)
	{
	case U8X8_MSG_BYTE_SET_DC:
	{
		if (u8g2_esp32_hal.dc != U8G2_ESP32_HAL_UNDEFINED)
		{
			gpio_set_level(u8g2_esp32_hal.dc, arg_int);
		}
		break;
	}

	case U8X8_MSG_BYTE_INIT:
	{
		if (u8g2_esp32_hal.sda == U8G2_ESP32_HAL_UNDEFINED ||
			u8g2_esp32_hal.scl == U8G2_ESP32_HAL_UNDEFINED)
		{
			break;
		}

		i2c_config_t conf;
		conf.mode = I2C_MODE_MASTER;
		ESP_LOGI(TAG, "sda_io_num %d", u8g2_esp32_hal.sda);
		conf.sda_io_num = u8g2_esp32_hal.sda;
		conf.sda_pullup_en = GPIO_PULLUP_ENABLE;
		ESP_LOGI(TAG, "scl_io_num %d", u8g2_esp32_hal.scl);
		conf.scl_io_num = u8g2_esp32_hal.scl;
		conf.scl_pullup_en = GPIO_PULLUP_ENABLE;
		ESP_LOGI(TAG, "clk_speed %d", I2C_MASTER_FREQ_HZ);
		conf.master.clk_speed = I2C_MASTER_FREQ_HZ;
		conf.clk_flags = 0;
		ESP_LOGI(TAG, "i2c_param_config %d", conf.mode);
		ESP_ERROR_CHECK(i2c_param_config(I2C_MASTER_NUM, &conf));
		ESP_LOGI(TAG, "i2c_driver_install %d", I2C_MASTER_NUM);
		ESP_ERROR_CHECK(i2c_driver_install(I2C_MASTER_NUM, conf.mode, I2C_MASTER_RX_BUF_DISABLE, I2C_MASTER_TX_BUF_DISABLE, 0));
		break;
	}

	case U8X8_MSG_BYTE_SEND:
	{
		uint8_t *data_ptr = (uint8_t *)arg_ptr;
		ESP_LOG_BUFFER_HEXDUMP(TAG, data_ptr, arg_int, ESP_LOG_VERBOSE);

		while (arg_int > 0)
		{
			ESP_ERROR_CHECK(i2c_master_write_byte(handle_i2c, *data_ptr, ACK_CHECK_EN));
			data_ptr++;
			arg_int--;
		}
		break;
	}

	case U8X8_MSG_BYTE_START_TRANSFER:
	{
		uint8_t i2c_address = u8x8_GetI2CAddress(u8x8);
		handle_i2c = i2c_cmd_link_create();
		ESP_LOGD(TAG, "Start I2C transfer to %02X.", i2c_address >> 1);
		ESP_ERROR_CHECK(i2c_master_start(handle_i2c));
		ESP_ERROR_CHECK(i2c_master_write_byte(handle_i2c, i2c_address | I2C_MASTER_WRITE, ACK_CHECK_EN));
		break;
	}

	case U8X8_MSG_BYTE_END_TRANSFER:
	{
		ESP_LOGD(TAG, "End I2C transfer.");
		ESP_ERROR_CHECK(i2c_master_stop(handle_i2c));
		ESP_ERROR_CHECK(i2c_master_cmd_begin(I2C_MASTER_NUM, handle_i2c, I2C_TIMEOUT_MS / portTICK_RATE_MS));
		i2c_cmd_link_delete(handle_i2c);
		break;
	}
	}
	return 0;
} // u8g2_esp32_i2c_byte_cb

/*
 * HAL callback function as prescribed by the U8G2 library.  This callback is invoked
 * to handle callbacks for GPIO and delay functions.
 */
uint8_t u8g2_esp32_gpio_and_delay_cb(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
{
	ESP_LOGD(TAG, "gpio_and_delay_cb: Received a msg: %d, arg_int: %d, arg_ptr: %p", msg, arg_int, arg_ptr);

	switch (msg)
	{
		// Initialize the GPIO and DELAY HAL functions.  If the pins for DC and RESET have been
		// specified then we define those pins as GPIO outputs.
	case U8X8_MSG_GPIO_AND_DELAY_INIT:
	{
		uint64_t bitmask = 0;
		if (u8g2_esp32_hal.dc != U8G2_ESP32_HAL_UNDEFINED)
		{
			bitmask = bitmask | (1ull << u8g2_esp32_hal.dc);
		}
		if (u8g2_esp32_hal.reset != U8G2_ESP32_HAL_UNDEFINED)
		{
			bitmask = bitmask | (1ull << u8g2_esp32_hal.reset);
		}
		if (u8g2_esp32_hal.cs != U8G2_ESP32_HAL_UNDEFINED)
		{
			bitmask = bitmask | (1ull << u8g2_esp32_hal.cs);
		}

		if (bitmask == 0)
		{
			break;
		}
		gpio_config_t gpioConfig;
		gpioConfig.pin_bit_mask = bitmask;
		gpioConfig.mode = GPIO_MODE_OUTPUT;
		gpioConfig.pull_up_en = GPIO_PULLUP_DISABLE;
		gpioConfig.pull_down_en = GPIO_PULLDOWN_ENABLE;
		gpioConfig.intr_type = GPIO_INTR_DISABLE;
		gpio_config(&gpioConfig);
		break;
	}

		// Set the GPIO reset pin to the value passed in through arg_int.
	case U8X8_MSG_GPIO_RESET:
		if (u8g2_esp32_hal.reset != U8G2_ESP32_HAL_UNDEFINED)
		{
			gpio_set_level(u8g2_esp32_hal.reset, arg_int);
		}
		break;
		// Set the GPIO client select pin to the value passed in through arg_int.
	case U8X8_MSG_GPIO_CS:
		if (u8g2_esp32_hal.cs != U8G2_ESP32_HAL_UNDEFINED)
		{
			gpio_set_level(u8g2_esp32_hal.cs, arg_int);
		}
		break;
		// Set the Software I²C pin to the value passed in through arg_int.
	case U8X8_MSG_GPIO_I2C_CLOCK:
		if (u8g2_esp32_hal.scl != U8G2_ESP32_HAL_UNDEFINED)
		{
			gpio_set_level(u8g2_esp32_hal.scl, arg_int);
			//				printf("%c",(arg_int==1?'C':'c'));
		}
		break;
		// Set the Software I²C pin to the value passed in through arg_int.
	case U8X8_MSG_GPIO_I2C_DATA:
		if (u8g2_esp32_hal.sda != U8G2_ESP32_HAL_UNDEFINED)
		{
			gpio_set_level(u8g2_esp32_hal.sda, arg_int);
			//				printf("%c",(arg_int==1?'D':'d'));
		}
		break;

		// Delay for the number of milliseconds passed in through arg_int.
	case U8X8_MSG_DELAY_MILLI:
		vTaskDelay(arg_int / portTICK_PERIOD_MS);
		break;
	}
	return 0;
} // u8g2_esp32_gpio_and_delay_cb
